Process for the precipitation of viscose for the production of artificial threads and other structures.



UNITED STATES PATENT OFFICE.

GUSTAV WALTHER, F CREFELD, GERMANY.

PROCESS FOR THE PRECIPITATION 'OF VISCOSE FOR THE PRODUCTION OF ARTIFICIAL THREADS AND OTHER STRUCTURES.

No Drawing.

To all whom it may concern;

Be it known that I, Dr. GUSTAV WAurHER, a subject of the German Emperor, residing at 16 Bissingstrasse, Crefeld, Germany,have invented "a new and useful Process for the Precipitation of Viscose for the Production of Artificial Threads and other Structures;

and I do hereby declare the following to be fate (French Patent No. 451276), glucose and sulfuric acid (British Patent No. 21405 of 1907), acids with salts and organic substances (GermanPatent No. 240846), or salt and formic acid (French Patent No. 438718). I

It is also known from the U. S. A. Patents Nos. 816404 and 849823, that threads can be produced from viscose by means of sodium bisulfite solution and subsequent treatment with acids. The properties of the threads obtained in this manner however leave something .to be desired.

According to the resent invention, very ood precipitation of the viscose can be efected by salts of the oxymethyl-ester of sulfurous acid, to which is attributed the following constitution:

OH,.OH ASQNa and other aldehyde bisulfites, as well as reduction products of aldehyde bisulfites like sulfoxylates omen soNa

Specification of Letters Patent.

Patented Jan. 28, 1919.

Application filed June 9, 1914. Serial 170. 844,034.

The threads precipitate out in a homogeneous, supple, extensible and transparent state. One advantage afforded by the baths remaining perfectly clear during the precipitation, is that irregularities in the spinning can be seen at once and remedied. Moreover the baths cleanse the thread being formed, brown streaks or striae flowing from them which quickly become colorless and disappear in passing through the bath. There are no gases of decomposition formed, like sulfureted hydro en, by, which the thread is easily injure and there is likewise no separation of sulfur. The precipitation baths act extremely gently, so that the separation of the threads is very favorable. Although still soluble in water,'the thread exhibits great firmness and elasticity. Even after remaining for a day or more on the spool it does not lose its good qualities and withstands further treatment such as twisting and winding very well.

sequent waste of material to take place. The

precipitated thread is rendered insoluble in water by subsequent treatment with diluted acids, or by heating or steaming.

By means of the new process the transformation of xanthogenatecellulose into viscose-silk can. be carried out very slowly, which has a favorable influence upon the properties" of the thread:

The following examples may be given for the precipitation baths a I. 300 grams of glucose are dissolved warm in 1000 grams of sodium bisulfite solution of 3536 Baum, and heated to 60 C. during spinning.

II. 300 }grams of 40% formaldehyde are mixed wi 1000 grams of sodium bisulfite solution of 36 Baum, and heated to 50 C. during spinning.

III. 186 grams of acetone are diluted with 200 grams of water, stirred up with 1000 grams of sodium bisulfite solution of 36 B aum, andheated to 50 C. during spinning."

IV. "377 grams of benzaldehyde are dissolved in 1000 grams of sodium bisulfite so-- lution of 36 Baum, and heated to 50 C. during spinning.

V 400 grams of rongalite are dissolved in 1000 grams of water and heated to 55 C.

during spinning.

The chemical composition of rongalite is cH OH (dSONa- VI. The product obtained from 94; grams of phenol, 250 grams of sodium sulfite and 7 6 grams of 40% formaldehyde, in accordance with Friedlander, Vol. IV, page 98, Example 4, is dissolved in 500 grams of water and heated to 55-60 C. during spinning.

According to requirements, the baths are employed either diluted or in other concentrations, and also at other temperatures than those mentioned. Moreover inorganic and organic salts, such as Glaubers salt, sodium acetate and similarly acting salts, as well as aldehyde-bisulfites (oxymethyl-ester of suliurous acid) and additional products with the addition of substances containing sugar; and decomposing and finishing the'precipitation product.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses.

D13. GUSTAV WALTHER.

Witnesses PAUL 'Vmns, HENRY AUSDFLUG; 

